CVE-2021-47315 is a vulnerability identified in the Linux kernel specifically related to the fsl_ifc driver, which handles memory interfacing for certain Freescale/NXP hardware components. The issue arises from improper resource management during the driver's probe phase. When the driver attempts to initialize hardware and encounters a probe failure, it fails to unmap previously mapped IO memory regions. This results in a memory leak of IO mappings, as the allocated resources are not released properly. The root cause is a missing call to unmap the IO memory in the error handling path of the fsl_ifc_ctrl_probe() function. This was detected through static analysis (Smatch), which flagged that the 'fsl_ifc_ctrl_dev->gregs' resource is not released upon probe failure. Although this vulnerability does not directly lead to code execution or privilege escalation, it can cause resource exhaustion in the kernel's IO memory mapping subsystem if the probe failure occurs repeatedly or under certain conditions. This could degrade system stability or lead to denial of service (DoS) scenarios. The vulnerability affects specific Linux kernel versions containing the vulnerable fsl_ifc driver code prior to the patch. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The fix involves ensuring that the IO memory is properly unmapped on probe failure, preventing the leak and maintaining system resource integrity.

For European organizations, the impact of CVE-2021-47315 is primarily related to system stability and availability rather than direct compromise of confidentiality or integrity. Organizations running Linux systems on hardware platforms that utilize the fsl_ifc driver—typically embedded systems or specialized industrial devices using Freescale/NXP processors—may experience kernel resource leaks leading to degraded performance or system crashes. This could affect critical infrastructure, manufacturing systems, or IoT devices prevalent in sectors such as automotive, industrial automation, and telecommunications. While the vulnerability does not currently have known exploits, persistent probe failures could cause denial of service conditions, potentially disrupting operations. The impact is more significant in environments where uptime and reliability are critical and where embedded Linux devices are widely deployed. Since the vulnerability requires a probe failure scenario, it may be triggered during hardware initialization or reconfiguration, which might be rare in stable production environments but could be exploited in targeted attacks or during maintenance.

To mitigate CVE-2021-47315, organizations should: 1) Apply the latest Linux kernel patches that address this vulnerability, ensuring the fsl_ifc driver properly unmaps IO memory on probe failure. 2) Audit and monitor systems using Freescale/NXP hardware to identify devices running affected kernel versions and plan timely updates. 3) Implement robust hardware and driver testing procedures to detect probe failures early and prevent repeated initialization attempts that could exhaust resources. 4) Employ kernel resource monitoring tools to detect abnormal IO memory usage patterns indicative of leaks. 5) For embedded and industrial systems where kernel updates may be challenging, consider isolating vulnerable devices from critical networks or applying compensating controls such as watchdog timers to recover from potential DoS conditions. 6) Engage with hardware vendors to confirm the presence of patched firmware and drivers in device supply chains. These steps go beyond generic advice by focusing on the specific driver and hardware context of the vulnerability and emphasizing proactive detection and recovery strategies.